Pellet mill



Aug. 26, 1958 P. BoNNAl-oux PELLET MILL 2 Sheets-Sheet l Filed July l5, 1955 paz/z. BQA/NAFOUX,

INVENTOR.

Aug' 25, 1958 P. BONNAFOUX 2,848,738

PELLET MILL Filed July 13, 1955 2 Sheets-Sheet 2 4 .pnl/z. oNNApoz/x,

IN V EN TOR.

rraQA/gg.

2,848,738 Patented Aug. 26, 1958 Fice PELLET MILL A Paul Bonnafoux, Lancaster, Calif.

Application July 13, 1955, Serial No. 521,781

3 Claims. (Cl. 18-12) This invention relates to a pellet mill and, more particularly, to a pellet mill of the rotary type wherein comminuted feeds and the like are fed into the mill and eX-l truded thereby in the shape of hard, glossy pellets of cylindrical cross section.

Conventional rotary pellet mills usually include a housing having an inlet for the comminuted and moistened feed or other material, and an outlet from which the pellets may be discharged. Located in the housing is a rotatable pellet forming die which is provided with a plurality of pellet forming orifices and in the interior of which there is positioned a roller having a serrated surface which is adapted to extrude the feed or other material through the orices in the die in an outward direction.

One of the major disadvantages of conventional, rotary pellet mills lies in the fact that relatively large power consumption is necessary to produce a relatively small quantity of pellets.

It is, therefore, an object of my invention to provide a rotary pellet mill wherein a plurality of rotatable dies is mounted `within and supports a roller so that the rotatable dies are in driven relationship with a surface provided on the interior of the roller and so that feed or other material can be fed into the interior of the housing in which the roller is located and forced inwardly through orifices provided in the dies with a slightly greater consumption of horsepower than that necessary for the energization of the single die in conventional rotary pellet mill constructions.

One of the major disadvantages of rotary pellet mills of conventional construction lies in the fact that the dies are necessarily of relatively small diameter and, therefore, the rollers located within the dies to extrude feed or other material therethrough are of correspondingly small diameter. The small diameters of the dies and rollers result in a relatively small nip between the periphery of the roller and the interior surface of the dies so that considerable diiculty is encountered in feeding the comminuted feed or other material between the roller and die surfaces and jamming of the roller within the die is a common occurrence.

Another problem encountered in the use of conventional rotary pellets mills is the fact that, since the rollers are located eccentrically with respect to the surface of the dies, and since the pressures generated between the roller and die surfaces are eXtreme and of the order of 40,000 p. s. i., bearing break-down is a common occurrence necessitating the tearing down of the conventional mills and the replacement of component parts of the bearings in which the dies and rollers are supported.

An additional object of my invention is the provision of a rotary pellet mill wherein the die members located within the roller are symmetrically arranged about the axis of rotation of the roller and thereby serve to support the roller at spaced points about its interior surface. ln this manner, the pellet forming pressures are equalized about the circumference of the roller and the eccentric bearing loads encountered in conventional rotary pellet mills are eliminated.

Furthermore, because of the equalization of bearing loads due to the symmetrical distribution of the dies about the interior of the circumference of the roller, the frictional losses encountered in conventional rotary pellet mills are eliminated and thus proportionally smaller horsepower motors can be utilized to drive the roller and dies with greater resultant production than is possible in the case of conventional rotary pellet mills.

Moreover, because the roller is supported on the plurality of rotatable dies, the bearing and surface wear which does occur is equally distributed among the bearings for all of the dies and the necessity for frequent servicing of a rotary pellet mill constructed in accordance with the teachings of my invention is eliminated.

Other objects and advantages of my invention will be apparent from the following specification and the accompanying drawings which are for the purpose of illustration `only and in which:

Fig. l is a vertical, side-elevational view of the housing of a rotary pellet mill constructed in accordance with the teachings of my invention;

Fig. 2 is a vertical, sectional view taken on the broken line 2 2 of Fig. l;

Fig. 3 is an enlarged, fragmentary view showing the relationship of a die with the interior circumferential surface on the roller;

Fig. 4 is an enlarged, fragmentary view in vertical section showing the relationship between the pellet forming orifices in the die and the adjacent surface of the roller; and

Fig. 5 is an enlarged, fragmentary view showing the relationship between the orifices in a die and roller in an alternative embodiment of the invention.

Referring to the drawings and particularly to Figs. 142 thereof, I show a rotary pellet mill 10 constructed in accordance with my invention and incorporated in a housing 12. The housing 12, as best shown in Figs. l and 3 of the drawings, is constituted by side plates 14 secured in operative relationship with each other by means of a cover 16 at their upper ends and at their lower ends bearing elongated angles 18 by means of which they are secured to a bed plate 20 and a bed 22 through the use of bolts 24.

Fastened to the exterior surfaces of the plates 14, as by means of welding, are supporting bars 26 which serve as mounts for pillow blocks 28 secured thereto in spaced pairs by means of bolts 30. Adjustment slots 32 are formed in the supporting bars 26, as best shown in Fig. 2 of the drawings, to permit the pillow blocks to be adjusted thereupon by the loosening of the bolts 30, for a purpose which will be described in greater detail below. Since all the bearings are located externally of the housing, they cannot be contaminated by the feed or subjected to intense heat within the roller `as in conventional pellet mills.

A first, uppermost rotary die 34 is, as best shown in Figs. l and 2 of the drawings, mounted for rotation within the housing 12 upon an axle 36 Whose opposite ends are journaled in a spaced pair of pillow blocks 2S, while a second, intermediate rotary die 38 is mounted withm the housing 12 in spaced relationship with the rst rotary die 34 upon an axle 40 whose opposite ends are mounted in another spaced pair of pillow blocks 28. In a similar manner, a third, lowermost rotary die 42 is mounted for rotation upon an axle 44 in spaced relationship with the first and second dies 34 and 38, respectively. Each of the rotary dies is, as best shown in Figs. 2 and 4 of the drawings, provided with a plurality of pellet forming orifices 46 which extend through the peripheral rim thereof in radial directions and the mounting of each of "d the dies is accomplished by the provisionrof a spider or hub 48 having a peripheral shoulder 50 thereupon forthe reception of an axially extending ilauge 52 which is adapted to receive bolts 54 for securing said hub in operative relationship vwith said llange.V A-

Mounted for rotation within the-housing 12 of the pellet-mill upon the'peripheries ofthe rotary dies 34, 38, and 42 is a roller 56, said roller, in the present embodiment of theinvention, being provided on its periphery with a plurality ofteeth- 58 Vengageable. by a drive belt 60 operatively connected to a driving sprocket 62 on an electric motor 64, as best showny in'Fig. l'of the drawings. The'interior circumferential surface 66 of the roller S6 is engaged upon the peripheries of .the rotary dies 34, 38, and 42 to drive said dies and is simultaneously supported for rotation thereupon..y It wouldzbe possible to provide intermeshing gears onthe roller-and dies to create a positive drive between the same.

One edge of each of the 'dies 34, 38, and 42 is, as best shown in Fig. '2 of ythe drawings, juxtaposed to thek inner surface `of one of the side plates 14 ofthe housing 12 and there is mounted within .the interior of the housing a baille plate 68 having a plurality of openings 70 formed therein for the reception of thehubs 48 of said rotary dies. Each of the openings '70 is, as best shown in Figs. 2 and 3 of the drawings, drawn .ona center spaced from the axis of rotation of thehubV 48 with which it is associated to provide an adjustment gap 72.to permit the adjustment of the peripheries of the rotary dies toward the adjacent inner sur-face 66 of the roller 56 to accommodate for wear occasioned in the surface of the roller 56 and to insure thateach of the rotary dies is adequately engaged upon said surface to assume its share ofthe burden of supporting said roller in the housing .12.

Moreover, it is essential that each of the rotary` dies have its surface in operative engagement with the surface 66 of the roller 56 so that van optimum driving relationship be established between the roller 56 and the individual rotary dies located therein.

The bathe plate 68is supported, as best shown in Fig. 2 of the drawings, upon the interior surface of the lefthand side wall 14 by means of brackets or spacers 74 and the bae plate 68, in conjunction with the roller 56 and the interior surface of the opposite side wall 14, thus constitutes a chamber 76 in which the rotary dies 34, 38, and 42 are located.

Communicating with the chamber 76 are spaced inlet Y chutes 78. The ends of the inlet chutes 78 are, as best shown in Fig. 1 of the drawings, so located that when the roller 56 is rotated in the clockwise direction indicated by the arrow 80, comminuted feed o r other material will be Ifed thereby `into the nips between the peripheral surfaces of the rotary dies 34,v 38, and 42 and the circumferential inner surface 66 on the roller 56.

A plurality of discharge chutes 84 is mounted in the side wall 14 ofthe housing 12 that supports the inletV chutes 78 and the ends thereof are located within the interior of the rotary dies 34, 38, and 42 to receive pellets which are cut from material extruded through the pellet forming orifices 46 in the dies by means of knives '86 whose blades are juxtaposed to the interior circumferences of each of the dies at points substantially opposite the nips between the exterior circumferences of the dies and the roller 56. Y

Therefore, when the roller 56 is rotated by the ener- Vgization of the motor 64 through the medium of the belt 60, concomitant rotation of the rotary dies 34, 38, and 42 will take place. If comminuted and moistened feed such as alfalfa is fed into the inlet chutes 78, a mass 88 thereof will be carried, as best shown in Fig. 3 of the drawings, into the nip between the periphery of each of the dies and the interior surface 66 on the roller 56. Because of the relatively largediameter of the roller 56 in relationship to the diameter of the rotary dies, there is a relatively large space at the nip of the dies with the interior surface 5'6 for the reception. of the mass 88of feed or other material.

Therefore, the rejection and jamming of the mass of ings, the feed is extruded thrpugh the pellet forming oriv iices 46 and as the dies are rotated in a clockwise direction simultaneously withl the similar rotation of the roller 56, the extruded material ultimately is engaged by the' blades of the knives 86 and the'pellets are cut therefrom and fall into the discharge chutes 84 and are ultimately deposited in a pellet receiving hopper 90.

lf Wear is occasioned on the inner surface 66k of the roller 56, the rotary dies can be adjusted toward the sur- -face 66 by loosening the bolts 30 in the pillow blocks 28 to permit the gap occasioned in the surface 66 to beaccommodated. Moreover, as clearly shown'byrFig. l of the drawings, the roller 56 is'supported at spaced points by the symmetrically located rotary diesy 34,' 38,- and 42 and thus both the surface wear and the bearing loads are distributed through the three rotary die members andare equalized thereby. In this manner, undue .wear in the bearings and surfaces occasioned .by eccentric positioning of the rollers in conventional rotary pellet mills is eliminated. Y

Shown in Fig. 5 of the drawings is an alternative embodiment of the inventionwherein there isprovided a roller 96 which incorporates a plurality of'pellet forming orifices 98 whichare staggered with respect to the pellet forming orifices provided in the rotary die members, such as the die member 34 shown in juxtaposition. to the roller 96. In such a construction, there is a dual pellet forming action since pellets are extruded. inwardly through the individualrotary dies, such as the die 34, and extruded outwardly and radially through'the orices 98 provided in the ro1ler19r6.

Since the three dies .34, 38, and 42 are utilized' in conjunction with the pellet forming roller 96,. it is neces? sary to provide three cutting blades, such as the blade 102, adjacent the-periphery of the roller 96 so that .the pellets extruded through the orices 98 in the roller can be cut from the periphery of theroller.. In order that a suflicient space may be providedfor the dischargeof the pellets, an auxiliary ilange104 is secured'to the edge of the roller 96 and is vprovided withl a peripheral circular baille plate 108 whichpprevents the pellets from falling freely outward into `the ,interiorof the housing 12.

VGear teeth 110are securedto the auxiliary ange 104 and are driven by a belt 112 to cause rotationof the roller 96.

A discharge chute, not shown, communicates with the space dened by the auxiliary llange 104 `and circular lbaille plate 108 at the lower portion ofthe :housing Vto accordance with the teachings .of my invention, it is pos-V sible to obtain a greater production of pellets without a substantial increase in the horsepowerusedto. drive Vthe rotary pellet mill. Moreover,-u`ndue.wear ilrboth bearings and engaging surfaces lis eliminated bythe symmetrical arrangement ofthe die members as supporting means for the roller in which they are located.. Furthermore, jamming and rejection of thefeed occasioned by the relatively smallspace at the nip offthe roller. and die in conventional constructions is eliminated because ofthe relatively large diameter of the roller with respect to the rotary die members incorporated therein providing a relatively large space at the nip of the dies with the roller into which a substantial mass of feed can be received.

I claim as my invention:

1. In a pellet mill, the combination of: a rotatable roller having a die-engaging surface formed on the interior thereof; and a plurality of rotatable dies mounted within said roller with their peripheries in supporting and driven relationship with said roller whereby said dies rotatably support said roller and said roller drives said dies, said dies having a plurality of pellet forming orices therein for the formation of pellets thereby.

2. In a pellet mill, the combination of: a rotatable roller having a die-engaging surface formed on the interior thereof and a plurality of pellet forming orifices communicating with said surface; and a plurality of rotatable dies mounted Within said roller with their peripheries in supporting and driven relationship with said roller whereby said dies rotatably support said roller and said roller drives said dies, said dies having a plurality 6 of pellet forming orifices therein for the formation of pellets thereby.

3. In a pellet mill, the combination of: a rotatable roller having a die-engaging surface formed on the interior thereof; and a plurality of rotatable dies mounted within said roll'er with their peripheries in supporting and driven relationship with said roller whereby said dies rotatably support said roller and said roller drives said dies, said dies having a plurality of pellet forming orifices therein for the formation of pellets thereby and being adjustable toward said surface to maintain contact therewith despite the wearing of said surface.

References Cited in the le of this patent UNITED STATES PATENTS 1,467,883 Sizer Sept. 1l, 1923 2,160,302 Billows May 30, 1939 2,174,141 Sizer Sept. 26, 1939 2,241,546 Evenstad et al'. May 13, 1941 FOREIGN PATENTS 159,369 Germany Aug. 26, 194() 

